This seems quite likely to be an issue with netplan; I've had a similar report on UC18; where systemd-networkd isn't started.
Turns out netplan moved the enablement of systemd-netwrokd to network- online.target; but unfortunately there may be no service or target depending on that. I'll revert the change to put systemd-networkd back under multi-user.target. ** Also affects: netplan.io (Ubuntu) Importance: Undecided Status: New ** Changed in: netplan.io (Ubuntu) Status: New => Triaged ** Changed in: netplan.io (Ubuntu) Importance: Undecided => Critical ** Changed in: netplan.io (Ubuntu) Assignee: (unassigned) => Mathieu Trudel-Lapierre (cyphermox) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821867 Title: network interface is down after post-install reboot of a default disco installation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1821867/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs